toolbarbutton

This functionality only applies when toolbarbutton is used in the 'Customize Toolbar' dialog.

The 'title' attribute sets the text that will be displayed as a button's label when it's in the 'Customize Toolbar' palette. It overrides the value of 'label', which is used if 'title' is not set. This does not affect the button's label when it is in a toolbar, which remains determined by the 'label' attribute.